Conventional methods for regenerating specific cells include methods such as administration of stem cells alone or growth factors, but there are functional limitations in actually proliferating and differentiating target cells. When stem cells are used alone, the rates of engraftment and survival of the administered stem cells are low and there is a limit in controlling the proliferation and differentiation even if the stem cells are alive. As the single administration of growth factors provides only a single effect, there is a limit in exhibiting sustained effects.
Recently, according to the study results from tissue regeneration and tissue engineering fields, an importance of the cellular microenvironment, i.e., “niche,” which corresponds to the external environment in which cells can regulate proliferation and differentiation is understood to be important to construct a simulated environment with biochemical and structural characteristics that can simulate the external niche.
In order to effectively achieve the intracellular environment, there are various techniques for searching for protein-protein interaction. Among them, phage display is a technique of discovering unknown amino acid sequences, which have the ability to bind to specific proteins, using recombinant bacteriophages produced by artificially introduced genes, which produce various amino acid sequences, into the genes of bacteriophages parasitic on bacteria. This technique is used in various applications, including epitope mapping, vaccine development, ligand-receptor affinity research, and bioactive peptide selecting (Smith G P, Scott J K. Libraries of peptides and proteins displayed on filamentous phage. Methods Enzymol. 279:377-380. 1993).
The representative M13 phage display system is designed to select phages, which have a strong ability to a specific protein, by a series of processes, including biopanning, using bacteriophages which express different peptides and are obtained by artificially inserting gene sequences into the ends of coat protein-producing genes of the bacteriophage genome so as to express peptides having 7-15 random amino acids and transfecting the bacteriophages into E. coli. When genomic DNA is artificially extracted from the selected bacteriophages and the nucleotide sequence of the artificially inserted DNA expressing specific peptides is analyzed, the desired functional peptide can be obtained.
On the other hand, it is known that specific biochemical cues in tissue ECMs play a critical role. However, the influence on the stem cells by role of physical cues such as stiffness has not been well studied.
Therefore, in a phage display, a specific coat protein is expressed on the phage surface using the phage genetic information and a polymer is used as an intermediate substance binding to the coat protein on the phage surface, thereby a nanofibrous structure of a specific strength generates through interaction between them, it can be used as a tissue matrix platform capable of inducing and regulating differentiation and proliferation of stem cells into specific cells.